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Diagnostic Test

  1. CHECK THE FUEL DELIVERY SYSTEM FOR LEAKS AND DAMAGE 
    WARNING:

    The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting, or line, the fuel system pressure must be released. Failure to follow these instructions can result in possible serious or fatal injury.

    1. Visually and physically inspect the fuel delivery system for external leaks and damage.

      Is the system leaking or damaged?

      Yes 

      • Repair or replace as necessary.
      • Perform the PCM VERIFICATION TEST. Refer to the appropriate Diagnostics & Testing article in Engine Performance .

      No 

      • Go To  2
  2. CHECK FUEL PUMP OPERATION 
    1. Ignition on, engine not running.
    2. With a scan tool, actuate the Fuel System test.
      NOTE:

      It may be necessary to use a mechanics stethoscope in the next step.

    3. Listen for fuel pump operation at the Fuel Tank.

      Does the Fuel Pump operate?

      Yes 

      • Go To  3

      No 

      • Check the power and ground circuits to the Fuel Pump Module assembly. If the circuits test good, replace the Fuel Pump Module assembly.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to the appropriate Diagnostics & Testing article in Engine Performance .
  3. INSTALL APPROPRIATE FUEL LINE ADAPTERS/FITTING FROM THE GAS AND DIESEL FUEL PRESSURE/DECAY TESTER 8978A 
    Fig 1: Fuel Line Adapters/Fitting
    GC0094811Courtesy of CHRYSLER GROUP, LLC
    1. Turn the ignition off.
      WARNING:

      The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting, or line, the fuel system pressure must be released. Failure to follow these instructions can result in possible serious or fatal injury.

    2. Release the fuel system pressure. Refer to FUEL DELIVERY, GAS, STANDARD PROCEDURE .
    3. Disconnect the rail fuel supply line connector between the fuel supply line and the fuel rail. Refer to FITTING, QUICK CONNECT, STANDARD PROCEDURE .
    4. Install the appropriate Fuel Line Adapters/Fitting from the Gas and Diesel Fuel Pressure/Decay Tester (special tool #8978A, Decay Tool, Fuel).

      Proceed 

      • Go To  4
  4. INSTALL THE FUEL PRESSURE GAUGE ASSEMBLY 
    Fig 2: Identifying Fuel Pressure Gauge Assembly
    GC0082754Courtesy of CHRYSLER GROUP, LLC
    1. Connect the (special tool #8978A, Decay Tool, Fuel), with the Fuel Inlet Hose (1) toward the Fuel tank side and the Fuel Outlet Hose (2) toward the fuel rail side of the system using the Fuel Line Adapters/Fitting as needed.
    2. Connect special tool Drain Extension Hose 535680 (3) to the Fuel Pressure Gauge Assembly Drain Hose (5).
    3. Connect Reservoir Assembly 534960 (4) to Drain Extension Hose 535680 (3).
      WARNING:

      To reduce the risk of fire and possible serious or fatal injury, place Reservoir Assembly 534960 (4) on the floor and out of the way so that it is not a trip hazard.

      Proceed 

      • Go To  5
  5. CHECK THE FUEL PRESSURE 
    Fig 3: Identifying Fuel System Isolation Valve & Flow Test Valves
    GC0082755Courtesy of CHRYSLER GROUP, LLC
    1. Perform the following procedure to purge air from the system:
      • Open the Fuel System Isolation Valve (1).
      • Close the Flow Test Valve (2).
      • Ignition on, engine not running.
      • With the scan tool, actuate the Fuel Pump.
      • Open the Flow Test Valve (2) for 10 seconds, then close the Valve.
      • CAUTION: Stop All Actuations. 
      • Turn the ignition off.
      • Disconnect, empty and then reconnect the Reservoir Assembly.
    2. Turn the ignition on.
    3. With the scan tool, actuate the Fuel Pump.
      NOTE:

      On vehicles equipped with a PWM Fuel Pump, actuate the Fuel Pump at or above 60%.

    4. Read the Fuel Pressure Gauge (3) and record the reading.
      NOTE:

      The fuel pressure specification for all engines, including a Non SRT-4  is 407 kPa +/- 34 kPa (59 psi +/- 5 psi). SRT-4  fuel pressure specification is 552 kPa +/- 34 kPa (80 psi +/- 5 psi).

      Choose a conclusion that best matches your fuel pressure reading.

      Below Specification 

      • Go To  10

      Within Specification 

      • Go To  6

      Above Specification 

      • Replace the fuel filter/fuel pressure regulator.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to the appropriate Diagnostics & Testing article in Engine Performance .
        CAUTION:

        Stop all actuation tests before proceeding.

  6. CHECK THE FUEL DELIVERY SYSTEM OUTPUT 
    Fig 4: Identifying Flow Test Valve And Reservoir Assembly
    GC0094812Courtesy of CHRYSLER GROUP, LLC
    WARNING:

    The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting, or line, the fuel system pressure must be released. Failure to follow these instructions can result in possible serious or fatal injury.

    1. With the scan tool, continue to actuate the fuel pump.
    2. Open the Flow Test Valve (1) for 20 seconds, then close the Valve.
      CAUTION:

      Stop all actuation tests before proceeding.

    3. Turn the ignition off.
    4. Measure the amount of fuel in the Reservoir Assembly (2). The fuel output specification is mL/s X 20 seconds = fuel flow in mL.
      FUEL FLOW
      ENGINE mL/s mL per 20 Seconds
      4 Cylinder and 6 Cylinder 20.8333 417
      8 Cylinder 38.88889 778
      SRT-4 50 1000
      10 cylinder 55.5 1110

      Does the amount of fuel in the reservoir meet or exceed the specification?

      Yes 

      • Go To  7

      No 

      • Go To  8
  7. CHECK THE FUEL DELIVERY SYSTEM FOR LEAK DOWN 
    Fig 5: Fuel Inlet And Fuel Outlet Pressure Gauges
    GC0082756Courtesy of CHRYSLER GROUP, LLC
    WARNING:

    The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting, or line, the fuel system pressure must be released. Failure to follow these instructions can result in possible serious or fatal injury.

    1. Ignition on, engine not running.
    2. With the scan tool, actuate the fuel pump.
    3. Close the Fuel System Isolation Valve (1).
      CAUTION:

      Stop all actuation tests before proceeding.

    4. Turn the ignition off and then wait five minutes before proceeding.
    5. Read the Fuel Inlet (2) and Fuel Outlet (3) Pressure Gauges. The pressure should not drop more than 10 psi on either gauge.

      Does the fuel pressure drop more than 10 psi?

      Yes - On Fuel Inlet Gauge (2) 

      • Replace the Fuel Pump Module.
      • Perform the PCM VERIFICATION TEST. Refer to the appropriate Diagnostics & Testing article in Engine Performance .

      Yes - On Fuel Outlet Gauge (3) 

      • Replace the leaking Fuel Injector(s).
      • Perform the PCM VERIFICATION TEST. Refer to the appropriate Diagnostics & Testing article in Engine Performance .

      No 

      • If directed here by another test, return to that test. Otherwise, test complete.
  8. CHECK FOR RESTRICTED FUEL SUPPLY LINE 
    Fig 6: Identifying Flow Test Valve And Reservoir Assembly
    GC0094812Courtesy of CHRYSLER GROUP, LLC
    WARNING:

    The fuel system is under a constant pressure even with the engine off. Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released.

    1. Turn the ignition off.
    2. Disconnect the Fuel Pressure Decay Tester.
    3. Raise the vehicle on a hoist, and disconnect the fuel pressure line at the Fuel Pump Module.
    4. Install the Fuel Pressure Decay Tester between the fuel supply line and the Fuel Pump Module.
    5. Again, purge air from the system.
    6. Ignition on, engine not running.
    7. With the scan tool, actuate the Fuel Pump.
    8. Open the Flow Test Valve (1) for 20 seconds, then close the Valve.
      CAUTION:

      Stop all actuation tests before proceeding.

    9. Turn the ignition off.
    10. Measure the amount of fuel in the Reservoir Assembly (2). The fuel output specification is mL/s X 20 seconds = fuel flow in mL.
      FUEL FLOW
      ENGINE mL/s mL per 20 Seconds
      4 Cylinder and 6 Cylinder 20.8333 417
      8 Cylinder 38.88889 778
      SRT-4 50 1000
      10 cylinder 55.5 1110

      Does the amount of fuel in the reservoir meet or exceed the specification?

      Yes 

      • Repair/replace fuel supply line as necessary.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to the appropriate Diagnostics & Testing article in Engine Performance .

      No 

      • Go To  9
        CAUTION:

        Stop all actuation tests before proceeding.

  9. CHECKING THE FUEL INLET STRAINER 
    WARNING:

    The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released. Failure to follow these instructions can result in possible serious or fatal injury.

    1. Turn the ignition off.
    2. Remove the Fuel Pump Module and inspect the Fuel Inlet Strainer.

      Is the Fuel Inlet Strainer plugged?

      Yes 

      • Replace the Fuel Pump Inlet Strainer.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to the appropriate Diagnostics & Testing article in Engine Performance .

      No 

      • Replace the Fuel Pump Module.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to the appropriate Diagnostics & Testing article in Engine Performance .
  10. CHECK FOR RESTRICTED FUEL SUPPLY LINE 
    Fig 7: Identifying Fuel System Isolation Valve & Flow Test Valves
    GC0082755Courtesy of CHRYSLER GROUP, LLC
    WARNING:

    The fuel system is under a constant pressure even with the engine off. Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released.

    1. Turn the ignition off.
    2. Disconnect the Fuel Pressure Decay Tool.
    3. Raise the vehicle on a hoist, and disconnect the fuel pressure line at the fuel pump module.
    4. Install the Fuel Pressure Decay Tool between the fuel supply line and the fuel pump module.
    5. Again, purge air from the system.
    6. Turn the ignition on.
    7. With the scan tool, actuate the Fuel Pump.
      NOTE:

      On vehicles equipped with a PWM Fuel Pump, actuate the Fuel Pump at or above 60%.

    8. Read the Fuel Pressure Gauge (3) and record the reading.
      NOTE:

      The fuel pressure specification for all engines, including a Non SRT-4  is 407 kPa +/- 34 kPa (59 psi +/- 5 psi). SRT-4  fuel pressure specification is 552 kPa +/- 34 kPa (80 psi +/- 5 psi).

      Is the fuel pressure now within specification?

      Yes 

      • Repair/replace fuel supply line as necessary.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to the appropriate Diagnostics & Testing article in Engine Performance .

      No 

      • Go To  11
        CAUTION:

        Stop all actuation tests before proceeding.

  11. CHECKING FUEL INLET STRAINER 
    WARNING:

    The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released. Failure to follow these instructions can result in possible serious or fatal injury.

    1. Turn the ignition off.
    2. Remove the Fuel Pump Module and inspect the Fuel Inlet Strainer.

      Is the Fuel Inlet Strainer plugged?

      Yes 

      • Replace the Fuel Pump Inlet Strainer.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to the appropriate Diagnostics & Testing article in Engine Performance .

      No 

      • Replace the Fuel Pump Module.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to the appropriate Diagnostics & Testing article in Engine Performance .
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